Ecosystems, Biomes, and Climate Change

Comprehensive vocabulary flashcards covering energy flows, trophic dynamics, biogeochemical cycles, global atmospheric and oceanic circulation, biomes, and the mechanisms and impacts of climate change.

Energy Flow

The one-way passage of energy through an ecosystem where energy is used inefficiently, lost as heat at each transition, and requires a continuous input of solar energy harvested by producers.

Materials Cycle

The continuous reuse and recycling of the exact same matter and chemical elements over and over through biogeochemical cycles in an ecosystem.

Food Chain

A linear sequence of organisms through which nutrients and energy pass, where arrows show the directional flow of energy across successive trophic levels.

Primary Producer

An organism situated at the base of the food chain, usually photosynthetic (such as plants or phytoplankton), that converts inorganic substances and solar energy into organic matter.

Apex Consumer

The highest-level consumer in an ecosystem that occupies the top trophic level without natural predators.

Chemoautotroph

An autotrophic organism that produces its own organic food using inorganic chemical energy sources, such as $H_2S$, rather than sunlight.

Gross Primary Productivity (GPP)

The total rate at which photosynthetic primary producers incorporate solar energy from the sun over a specific period.

Net Primary Productivity (NPP)

The energy remaining in primary producer tissues after accounting for cellular respiration and heat loss, representing the energy available to the next trophic level.

Ecological Efficiency (10% Rule)

The measure of energy transfer efficiency between trophic levels, wherein on average only about $10\%$ of energy is passed to the next level.

Assimilation

The amount of an organism's acquired energy and nutrients incorporated into its own biological structures after accounting for incomplete ingestion.

Biomass

The total mass of living or previously living organisms within a unit area at the time of measurement within a given trophic level.

Biomagnification

The increasing concentration of persistent, toxic substances (such as PCBs) in the bodies of organisms at successively higher trophic levels in a food web.

Food Web

A graphic representation of a holistic, non-linear network of primary producers, primary consumers, and higher-level consumers describing ecosystem structure and dynamics.

Nitrogen Fixation

The conversion of gaseous atmospheric nitrogen ($N_2$) into biologically available organic or inorganic compounds, performed primarily by nitrogen-fixing bacteria.

Biome

A broad geographic area characterized by a distinct community of organisms and vegetation shaped predominantly by regional climate patterns.

Solar Radiation Angle

The primary control on Earth's surface temperature, determined by whether solar rays strike perpendicular to the surface (concentrated energy) or at an oblique angle (dispersed energy).

Coriolis Effect

The deflection of prevailing wind and water currents caused by Earth's west-to-east rotation, turning paths to the right in the Northern Hemisphere and to the left in the Southern Hemisphere.

Hadley Cell

A large-scale atmospheric circulation cell where warm, moist air rises at the equator, cools, and sinks as dry, dense air at approximately $30^\circ$ north and south latitude.

Relative Humidity

The percentage of water vapor present in a parcel of air relative to the maximum capacity it can hold at a given temperature, which rises as air cools.

Rain Shadow

A dry, arid region on the leeward side of a mountain range facing away from prevailing winds, created because rising air cools and sheds moisture on the windward side and warms while absorbing moisture as it descends.

Photic Zone

The upper layer of an aquatic biome extending to a depth of approximately $200\,\text{m}$ where sunlight penetration is sufficient for photosynthesis.

Ocean Upwelling

A process where offshore surface winds drive warm surface water away from coastlines, allowing cold, nutrient-rich deep ocean water to rise to the surface.

Lake Turnover

The seasonal vertical mixing of lake waters in spring and fall that moves oxygen and nutrients between deep and surface layers, driven by water reaching its maximum density at $4^\circ\text{C}$.

Weather

The short-term, day-to-day atmospheric conditions (such as temperature, precipitation, and wind) occurring in a particular localized area.

Climate

The long-term average of weather conditions and recurring patterns measured over decades or longer in a specific region.

El Niño-Southern Oscillation (ENSO)

A naturally occurring, irregular climate pattern in the tropical Pacific Ocean that fluctuates across $2\text{ to }7\text{ year}$ cycles.

North Atlantic Oscillation (NAO)

A climate pattern centered over the North Atlantic during winter with fluctuating atmospheric phases that persist for weeks to months.

Pacific Decadal Oscillation (PDO)

A recurring ocean-atmosphere climate pattern located in the North Pacific Ocean that fluctuates on a $10\text{ to }17\text{ year}$ cycle.

Climate Proxy

Preserved natural archives—such as ice cores, tree rings, glacier lengths, pollen records, ocean sediments, and coral cores—used to reconstruct past environmental and atmospheric conditions.

Albedo Effect

The reflectivity of solar radiation by Earth's surfaces, where reflective ice and snow keep regions cool, while loss of reflective cover creates a positive feedback loop of increased heat absorption.

Greenhouse Effect

The trapping of outgoing thermal radiation by atmospheric gases (such as $CO_2$ and $CH_4$) and its subsequent re-emission toward Earth, warming the lower atmosphere.

Ocean Acidification

The decrease in seawater pH resulting from the absorption of excess atmospheric $CO_2$, forming carbonic acid ($H_2CO_3$) and depleting carbonate ions needed by shell-forming organisms.

Anthropocene Ecology

The study of ecosystems in which human activities are as influential as natural processes in shaping ecological patterns, processes, and global environmental change.